Circular polarized patch antenna with wide 3‐dB axial ratio beamwidth and suppressed backward cross‐polarized radiation for high‐precision marine navigation applications

Abstract Here, a circular polarized (CP) patch antenna with a wide 3‐dB axial ratio beamwidth (ARBW) and suppressed backward cross‐polarized radiation is proposed. A narrow slot is inserted into the ground to widen the 3‐dB ARBWs of the CP antenna. An annular metal strip loaded with a circular row of L‐shaped bent metal branches is etched around the circular radiation patch to reduce backward cross‐polarized radiation, as well as to further increase the 3‐dB ARBW. To validate, a prototype is designed at 1.575 GHz and fabricated. The experimental results show that the 10‐dB impedance matching bandwidth of the fabricated prototype is 25.8%, and the 3‐dB CP bandwidth is 5.1%. Besides, 3‐dB ARBWs of 238° and 259° are obtained at the two principal planes, respectively, with the front‐back ratio of more than 26 dB. Satisfactory agreement is achieved between measurement results and simulated ones